Pressed metal clamp and method of producing same



MaichZB, 1937. P D. MERRILL PRESSEDMETAL CLAMPAND METHOD OF PRODUCING SAME- Filed Feb. '15. 1935 f 7206721 07" 15073 Q/ffririll' Patented Mar. 23, 1937 PRESSED METAL CLAMP AND METHOD 0F PRODUCING SAME Patterson D. Merrill, South- Bend, Ind., assignor to M. B. Skinner Company, South Bend, Ind., a corporation of Indiana Application February 15, 1935, Serial No. 6,653

2 Claims. (Cl. 138-99) Figure l is an elevational view of my improved clamp in use;

Figure 2 is an end view of the clamp of Fig. 1,

and being a section taken on the line 2-2 of.

Fig. 1;

Figure 3 shows a preliminary step in the process of making the clamp;

Figures 4 and. 5 show subsequent steps in the process;

Figure 6 is a view of the mechanism of Fig. 5, taken from another direction;

Figure 7 shows a final step; and

Figure 8 is a plan view of the completed clamp body.

Referring to the illustrations of the drawing,

the novel features of my invention reside chiefly in the improved clamp bodies 8' adapted to be clamped together by the usual bolts 9,.

A preferred step in the production of my improved clamp body consists in the selection'of a suitable sheet metal blank such as the elongated fiat steel plate I ll, adapted in length and width to the size of the pipe with which it is intended to be used, and desirably about three-sixteenths of an inch thick. This plate is subjected to a pressing or other forming operation, for instance while hot, being acted upon by suitable forming tools such as the lower and upper dies l I and i2. These die blocks are complementarily shaped, as by the concavity l3 in the lower die block and convexity M in the upper die block, to form the central portion of plate Ill into arcuate formation as indicated at Hi, (this are being somewhat less than a semi-circle) and leaving angular portions l6 at each end of the arcuate portion or body proper 15 (Figs. 4, 5 and 6), which are thus bent to form somewhat radially directed flanges.

In order to properly center the portion l5 longitudinally of the blank with respect to the angular portions I6, the blank may be first disposed between gauge shoulders I! carried by the lower die II and spaced apart an appropriate distance substantially equal to the length of the blank Ill. A pointed plunger I8 pricks the blank [0 upon its under surface as the upper die l2 closes down upon it, and serves to guard against shifting of the blank when its ends leave the gauge shoulders ll as the blank is shortened to bend it into arcuate form.

As is well known in the art, the plunger 18 yields to the movement of the upper die and is retracted into a recess I!) in the lower die against the force of a coil spring 2i) which later returns the plunger to its uppermost position for a subsequent operation. For a purpose presently pointed out, the surfaces 2| adjoining the arcuate concave face E3 of the lower die, and, correspondingly, the surfaces 22 adjoining the convex face It of the upperdie are slightly downwardly sloping from the ho-rizontahso as to give the angular portion It a slight angularity toward the outer face of the arcuate portion, in other words somewhat sharpening the angle at 23 between respective portions 15 and I6.

As the next preferred step in the production of the body 8 of the clamp, the preformed blank shown in Figs. 4, 5 and 6, having the arcuate portion or body proper l5 and angular end por tions or flanges H3, is subjected to another pair of forming means such as the lower jaw 24 and upper jaw 25, the lower jaw 24 having a convex face 26, corresponding to the arcuate portion l5 of the blank, and also having longitudinally aligned anvils 21 at each end of the arc. The anvils 2! have upper surfaces 21w corresponding to the lower surfaces of the angular portions [6 in the middle of these portions, but the anvils 21 being of reduced width with respect to the width of the blank, the transverse edges of the portions iii are unsupported.

The upper jaw 25 has a concavity 28 corresponding to the upper face of the portion I5 but of larger arcuity so that the are 28 is substantially a semi-circle. The upper jaw 25 has longitudinally aligned recesses 29 receiving the anvils 21 of the lower jaw, and these recesses 29 have upper walls 29a corresponding to the inclination of the angular portions 16. The upper jaw 25 therefore has a pair of formers 30 at each end, on each side of the recesses 29, so that when the jaws 24, 25 are closed together, the jointly inverted U-shape formers 30 bend the transverse margins of the portions I6 of the blank downwardly about each side of the anvils 21, as shown in Fig. 7, providing outwardly directed channel-like portions 3| at each end of the blank, these channel-like portions forming upset lugs or bosses for engagement by the bolts 9 for clamping purposes, tangentially of the bodies 8, as shown in Figs. 1 and 2.

It will be noted that the width of the body 8 at each end is reduced as at 33, the metal being upset in a transverse direction and thus being used to reinforce the lugs 3| in the direction of the pull of the bolts 9. Thus the original thickness of the metal of the flanges (i. e. about 1%", the same as the body I5) is retained to dispose a maximum amount of metal in the side walls of the channels which form reinforcing strut members, between the bottoms of the channels (that is the portions of the channel in which the bolt holes 34 appear) and the body proper l 5. Also, it will be noted, as best shown in Figs. 4, 5 and 6, that the channel-like lugs are initially somewhat radially directed by reason of the novel inclination given to the angular portions l6 of the blank.

Each of the lugs 3| is perforated desirably with a non-circular, in this instance a square, hole 34 through which is passed one of the bolts 9. Assuming that the pipe 35 has a break 36 therein, the rubber gasket 31 for example is placed over the break 36, in accordance with common well-known practice, and my improved clamp may then be applied to retain the gasket 31 in position, two of the clamp bodies 8 being placed end to end about the pipe and the bolts 9 passed through each pair of aligned holes 34 in the aligned semi-circular clamp bodies. By means of the nuts 38, adjacent ends of the clamp bodies 8 are drawn together about the pipe and a tight and secure engagement effected. The bolts 9 advantageously have square shank parts 39 just beneath their heads which are snugly received in the square holes to prevent turning of the bolts when the nuts are tightened.

So constructed and arranged, the clamp is heavy enough to provide a permanent repair to the pipe, and frequently to outlast the pipe, while still being sufliciently flexible to permit it to conform to irregularities on the pipe surface. The improved clamp has this distinct advantage of flexibility over, for example, a cast or forged construction, while at the same time the cost of my improved clamp is relatively low. Furthermore,

this low cost is made possible with no appreciable loss of strength and efficiency, but rather with an enhancement thereof, since the novel somewhat wedge-shape lugs which I have shown prevent any give or collapse of the lugs. Thus the full amount of take-up pressure applied by the bolts is transmitted directly to the clamp body 8 as a whole and through this to the gasket 31, ensuring maximum pressure upon the gasket 31 at the point of weakness in the pipe.

The angularity given to the angular portions I6, which I have already described, ensures that when the bolts are tightened as shown in Figs. 1 and 2 and the ends of the clamp bodies drawn toward each other, the angularity of the portions l6 will compensate for their tendency otherwise to slope toward each other, upon adjacent clamp ends, and the portions I6 will be drawn into parallel relation by the bolts. Thus the heads 40 of the bolts, and the nuts 38, make contact with the lugs 3| at all points.

The clamp bodies 8 are identical and are thus interchangeable. If desired also, one only of the clamp bodies could be used by welding it to the pipe 35, it being well adapted to become practically an integral part of the pipe in this way.

Having described my invention, I claim:

1. A pressed metal clamp member of the class described for use with clamping bolts embodying a preformed rectangular steel plate having a somewhat flexible arcuate body and somewhat radially directed flanges at each end of the body, said flanges being thereafter upset to form somewhat U-shape open-ended channels to retain a maximum amount of the metal of said flanges in the side walls of the channels which thus form reinforcing strut members between the bottoms of the channels and the said body, the bottoms of said channels being perforated to provide bolt lugs, whereby said lugs are materially stiffened in the direction of pull of the bolts while leaving the body somewhat flexible.

2. The structure of claim 1 wherein the bottom of each channel is perforated by a non-circular hole whereby a non-circular shank portion of the bolt may be snugly received in said bolt to prevent relative rotation of the bolt and clamp.

PATTERSON D. MERRILL. 

